"During the early '70s, many colleges across the country were having vacancies, and some schools actually turned residency halls into offices," says Ed Hendricks, president of the Association of College and University Housing Officers (ACUHO). But a recent survey of the 600 ACUHO institutions shows that large universities now are "all at capacity or over."

The result: Students are packing into the nooks and crannies of residence halls, tripling up in rooms built for two, living in lounges and study rooms, and sometimes even being sent off campus to live in motel rooms, trailers, and university-owned apartments.

At Boston University, 108 students -- who call themselves "nomads" -- are living in converted study rooms and lounges, waiting to be assigned to permanent rooms. All of them will have permanent assignments when they come back to school aftern Christmas, say administrators, who plan to fill spaces vacated by students who graduate, drop out, transfer, or move our on their own.

"Dormitories have historically been overbooked, because they [dormitory residents] were trimmed by the attrition rate," says Doug Tuttle, president of the US student Association. "But in the last couple of years the attrition rate hasn't been high enough."

In the 1960s and early 1970s, many students left the ubiquitous beige walls and stale popcorn smell of the dormitories to live in apartments and private homes. but less-available and higher-priced outside housing, coupled with the inconvenience of commuting and keeping house, has driven students back to university barracks.

"Of course, four or five students can share an apartment, buy food together, and still live cheaper than in a residence hall," says Mr. Hendricks. "But the time they have to spend doing that has become too valuable."

Now with dorm rooms being snatched up, some creative approaches have emerged.

At the University of California at Irvine some students drive in, plug in, and live in their own recreational vehicles.University officials say a housing shortage prompted them to build the 80 space park, dubbed Irvine Meadows West.

Students pay $70 a month, including utilities, to park Winebagos and Airstreams on a university-owned graveled plot. In contrast, the rate for a one-bedroom apartment in the surrounding community is $440 a month.

"I love it," says Martha Mayes, a dance major from Long Beach, Calif., who came to school last year with her family's 20-foot trailer in tow. "It's a lot cheaper than the dorm." She first heard about the park through a brochure sent to students on the school's dormitory waiting list.

Georgetown University in Washington, D.C., puts students up in 30 university-owned town houses in the exclusive neighborhoods adjacent to the school. About 100 students, paying $148 a month each, share them. Each house would fetch as much as $1,200 a month on the open market.

meanwhile, 30 students at Lyndon College in Lyndon, Vt., are living in local motels this year. The students pay about the same as they would for an on-campus spot. Although the idea of placing an overflow of students in motels (and hotels) is not new, it has mostly been restricted to large urban universities which have a reputation for absorbing local real estate of all kinds.

So while scrambling for temporary solutions, many colleges seem to be counting on the predicted decline in future enrollments to take the pressure off the housing pinch.

You're not going to see very many of the traditional dorms or residency halls being built," says ACUHO's Ed Hendricks. "The trend is going to be toward any sort of flexible housing" -- buildings that can be altered to meet the demand.